The class of polymers of carbon monoxide and olefin(s) has been known for some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators, e.g., peroxy compounds. U.K. 1,081,304 produced similar polymers of higher carbon monoxide content in the presence of alkylphosphine complexes of palladium salts as catalyst. Nozaki extended the reaction to produce linear alternating polymers in the presence of arylphosphine complexes of palladium moieties and certain inert solvents. See, for example, U.S. Pat. No. 3,694,412.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon has become of greater interest in part because of the greater availability of the polymers. More recent processes for the production of these polymers, now known as polyketones or polyketone polymers, are illustrated by a number of published European Patent Applications including 121,965, 181,014, 213,671 and 257,663. The process, now considered broadly conventional, typically involves the use of a catalyst formed from a Group VIII metal selected from palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa below about 6, preferably below 2, and a bidentate ligand of phosphorus, arsenic or antimony.
The resulting polyketone polymers are relatively high molecular weight materials having established utility as premium thermoplastics in the production of shaped articles by methods conventional for the processing of thermoplastics. Although the polymers are relatively stable, the linear alternating polymers do undergo some loss of desirable properties when exposed to heat for extended periods or when subjected to repeated cycles of melting and solidification.
Russell et al, U.S. Pat. No. 3,929,729 and U.S. Pat. No. 4,024,104, do teach the use of certain hindered phenolic benzophenones and benzotriazoles as thermal stabilizers of certain polymers of carbon monoxide and ethylene with the optional presence of third monomers. The scope of the disclosure of polymers by Russell et al is rather broad and includes linear alternating polymers, but the scope of materials tested by Russell et al is rather narrow and the teachings of Russell et al do not appear to be directed toward linear alternating polymers. Although a variety of phenolic materials has been conventionally employed to provide heat and melt stability to other classes of polymers, it would be of advantage to provide materials which provide improved thermal stability and improved melt stability to linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon.